1. Field of the Invention
The present invention relates to a pneumatic hand tool, and more particularly to a pneumatic hand tool which is compact is size and low cost.
2. Description of the Prior Art
The current available pneumatic hand tool is shown in FIG. 9, which includes a body (90), a cylinder (91), a rotor (92), a bearing (93), a sealing cap (94) and a control knob (95). The conventional pneumatic hand tool as shown is characterized in that the sealing cap (94) is firmly secured to a rear side of the body (90) so as to sealingly encase and position the cylinder (91), the rotor (92) and the bearing (93) inside the body (90). The sealing cap (94) is provided with an inlet passage and a pair of mutually corresponding air conducting passages incorporative with the control knob (95) to control and adjust the air path and air volume entering the cylinder (91). Accordingly, the rotation direction and rotational torque of the pneumatic hand tool is controlled.
Although this structural arrangement does satisfy the designed goals, the separation of the control knob (95) and the cylinder (91) limits that the body (90) has to be made of a metal material and the airtight capability has to be enhanced so as to accomplish safety requirements. Enhancing safety abilities of this conventional pneumatic hand tool increases the manufacture cost. Also, the metal material limitation for the production of the body (90) results in that the overall weight of the pneumatic hand tool is heavy. As a result of heavy weight of the hand tool, it is not easy for the user to operate the hand tool.
To overcome the shortcomings, the present invention tends to provide a novel pneumatic hand tool to mitigate the aforementioned problems.